Processing of the amyloid precursor protein (APP) by two different proteases, called alpha- and beta-secretase, is a central regulatory event in the generation of the amyloid beta peptide (Abeta), which has a key role in Alzheimer disease (AD) pathogenesis. TMEM59, a Golgi-localized protein, modulates the O-glycosylation and complex N-glycosylation steps occurring during the Golgi maturation of several proteins such as APP, BACE1, SEAP or PRNP. It inhibits APP transport and shedding.Synonyms: C1orf8, HSPC001, Liver membrane-bound protein, Transmembrane protein 59